Variables

Variables serve as containers for storing data values in memory.

Syntax: variable_name = value

Key characteristics:

• No explicit type declaration required
• Type is automatically determined from assigned value
• Variables must be assigned before use

# Variable definition and usage
value = 20
print(value)

Data Types

Python supports several built-in data types:

Core Data Types

• Numeric Types: int, float, complex, bool
• String: Ordered character sequences enclosed in quotes
• List: Mutable ordered collection using []
• Tuple: Immutable ordered collection using ()
• Set: Unordered unique collection using {}
• Dictionary: Key-value pairs using {}

Type Examples

# Numeric types
integer_val = 42
float_val = 3.14159
complex_val = 2+3j
bool_val = True

# String types
single_quoted = 'text'
double_quoted = "text"
triple_quoted = """multiline
text"""

# Collection types
sample_list = [1, 'item', 3.14]
sample_tuple = (5, 'hello')
sample_set = {'apple', 42, 'banana'}
sample_dict = {"name": "John", "age": 25}

Type Inspection

# Check variable type
person = {"name": "Alice", "age": 30}
print(type(person))  # Output: <class 'dict'>

Numeric Data Types

Integer Type (int)

Integers support multiple base representations:

# Different integer representations
decimal_val = 15
binary_val = 0b1111    # Binary
octal_val = 0o17       # Octal  
hex_val = 0xF          # Hexadecimal

Base Conversion Functions

# Base conversion examples
num = 18
print(bin(num))    # 0b10010
print(oct(num))    # 0o22
print(hex(num))    # 0x12

Floating-Point Type (float)

Represents decimal numbers:

pi = 3.14159
scientific = 2.5e-3  # 0.0025

Complex Type (complex)

comp_num = 4 + 7j
print(comp_num.real)  # 4.0
print(comp_num.imag)  # 7.0

Boolean Type (bool)

Special integer subtype where True = 1 and False = 0

Falsy values in Python:

• None
• False
• Zero values: 0, 0.0, 0j
• Empty sequences: "", (), []
• Empty dictionaries: {}

print(bool(""))     # False
print(bool(0))      # False  
print(bool("text")) # True

Type Conversion

# Type conversion examples
float_num = 7.8
print(int(float_num))    # 7
print(float(10))         # 10.0
print(complex(5))        # (5+0j)

Input and Output

Input Function

user_input = input("Enter value: ")
# Returns string type

Print Function

print("Hello", "World", sep="-", end="!")
# Output: Hello-World!

Operators

Arithmetic Operators

Comparison Operators

Assignment Operators

Bitwise Operators

Assume: a = 60 (binary: 0011 1100), b = 13 (binary: 0000 1101)